1. Field of the Invention
The present invention relates generally to a system and method for routing a telephone call, and more particularly to a system and method for routing a telephone call from a calling party to a called party's optimal location.
2. Background of the Invention
An organization with a large number of locations often subscribes to a “closest location call routing” service from its telephone company. The closest location call routing service terminates a call intended for the organization (the subscriber) to the subscriber's location that is physically closest to the caller. The closest location call routing service is particularly useful to a subscriber having multiple locations scattered throughout a large geographical area. The service is useful to the subscriber because the subscriber needs to advertise only one designated telephone number for all of its multiple locations. A caller dialing the designated telephone number of the subscriber will always be connected to a location that is physically closest to the caller, no matter where the caller originated the call from.
Currently, the closest location call routing service is implemented as follows: First, a database is created at a service control point (SCP). The database associates a calling number with its location based on the zip code, the wire center, or other area-related granularity of the caller. The database at the SCP (referred herein as “the SCP database”) identifies a forwarding telephone number (or the route-to number) based on a customer's desired granularity. For example, if the desired granularity is based on zip codes, all calls originating from an area within the same zip code are routed to the same forwarding telephone number.
The SCP database also contains one designated telephone number and all other telephone numbers of the subscriber. For example, a subscriber having four service locations, one in each of a city's four quadrants, may select “555-5555” as the designated telephone number, for all calls intended for its northwest, northeast, southeast, and southwest locations having actual telephone numbers of “111-1111,” “222-2222,” “333-3333,” and “444-4444,” respectively. When a call is received from a caller dialing the designated telephone number, the SCP database is queried to determine which of the subscriber's four telephone numbers should be used to route the call. In the above example, the SCP database and the SCP are programmed such that a caller dialing “555-5555” from the northwest quadrant of the city will be connected to the subscriber's northwest location that has the telephone number “111-1111.” Similarly, another caller who is physically located in the subscriber's southeast quadrant of the city who dials “555-5555” will be routed to the southeast branch having the “333-3333” telephone number.
In the prior art systems, the closest location of the called party is determined based on the SCP database or other huge databases. Other prior art systems locate the caller by using the identity of the central office of the caller, or by looking up the caller's zip code based on the caller's telephone number. These applications have limited level of granularity. For example, a subscriber cannot divide a zip code such a way that half of the calls from that zip code are routed to location A and the other half of the calls are routed to location B. Furthermore, a zip code may cover a large geographical region.
Existing closest location call routing systems that rely on SCP databases have the following disadvantages. First, a subscriber to the service must work with a third-party vendor to generate the needed information for the SCP. The third party usually converts data from Geographic Information Systems (GIS) format to a different format suitable for the database at the SCP. In doing so, much of the advantages of the GIS technology is lost due to data format conversion. Second, periodic updates to the SCP database are needed due to, among other things, area code changes, expansion of the subscriber's market, and addition or deletion of subscriber locations. Third, the positioning of the caller and the closest location determination is limited to fixed granularity like zip code or wire center based on a caller's NPA-NXX-XXXX. Fourth, the existing systems require one or more huge databases at the SCP. Fifth, maintenance of the SCP database is difficult and expensive. Sixth, the location-finding algorithms at the SCP are complex and difficult to implement. In short, relying on the SCP alone for closest location call routing is inefficient.